The following main geologic and technological problems are solved in an open hole of vertical, directional and horizontal oil and gas wells during prospecting, exploratory, production and operating drilling by production departments of LLC «Gazprom geofizika»:
– lithologic and stratigraphic layering and correlation of well log;
– quality discrimination of reservoirs of all types in well log and determination of their parameters;
– separation of reservoirs into productive and water-bearing ones and separation of productive reservoirs into gas pays and oil pays;
– determination of positions of hydrocarbon contacts, the presence and characteristics of transition zones, net gas and oil thickness;
– determination of porosity, gas saturation, oil saturation, permeability recovery factors;
– determination of reservoir pressures and temperatures;
– determination of formation heterogeneity;
– potential production forecasting;
– forecasting of geologic section in the borehole environment and in the inter-well space;
– determination of spatial position of bore hole and conformity of well trajectory to the design;
– determination of well bore section geometry, detection of keyseats, caverns, seal glands, clay warping and flow areas, forecasting of sticky zones;
– detection of fluid shows and adsorptions.
Selection of the most rational complex of survey methods to achieve the highest informativity and economical efficiency of the studies is performed in close cooperation with Geological survey departments of Customers. Advisability of the complex is determined primarily by the features of subsurface geology, well designation, its design features, properties of drilling mud and flush fluid used during well construction.
LLC «Gazprom geofizika» has wide range of certified digital borehole instrumentation of modular design, modern recording systems manufactured by leading Russian manufactures.
The “rigid” cable technology as well as self-contained hardware-methodical complexes lowered on drill pipes are used for surveying of wells with horizontal borehole end and wells with large borehole inclination angles.
The obtained geophysical data are processed in the interpretation centers of production departments.
Electronic and satellite communication facilities are used to provide operativeness of interpretation operations.